Add --log-level support - Issue #5198

I noticed that even if I set the log level to 'fatal' there are still quite a few things printed to stdout/err.
In my quick scan its because not everything is using the default logger.  For example, I noticed that
job.go has its own.  I think that should be removed and everyone should use the same logger.
I could move that change into this PR if people want, but I'd prefer to split it out into a new one so that
this one is just focused on adding the --log-level flag.

Closes #5198

Signed-off-by: Doug Davis <dug@us.ibm.com>
well, yes its the most verbose today but if a new level comes along that even more verbose then -D should have no impact and I wouldn't want to just blindly set our loglevel to debug, I'd still want to compare with what's already set.  This goes back to my comment/concern above about hard-coding the assumption that debug is always the most verbose.